KundoWhite
Kundo 400-Day Anniversary Clock
Deseret Industries, $35, 2013-03-06
Uses 0.0032" suspension spring
Regulation Screw:
- Clockwise = Slower
- Counter-Clockwise = Faster
2013-11-27 ==========
Suspension spring replacement
The suspension spring is broken. In fact, it appears that someone attempted to spin the pendulum many turns, perhaps thinking that was how the clock was wound. Needless to say, the suspension spring snapped and is broken at the bottom block.
I removed the bottom block from the pendulum with some difficulty. At least, with the suspension spring broken, I didn't have to attempt this while still installed in the clock, rather, I was able to remove the pundulum assembly and work on it more easily alone. The bottom block is held in place by a pin that itself is held by a spring-loaded collar which prevents the pin from slipping out when the pendulum is secured for shipment. Sadly, the pin is VERY tight in it hole, which leaves the collar as an extra safety element that really isn't doing any work. I was able to remove the pin with a great deal of effort by turning the pendulum from the vertical, and then pressing into the pin with a pointed tack, and with enough leaning and pushing I was finally able to get the pin removed.
Some of the reading I've done indicates this was done to keep the pin in place during shipment, but then what's the collar for, I wonder? In any case, the references suggest filing the pin smooth, removing the central bulge, so that the pin can be re-inserted easily and this is what I did.
A quick measurment of the distance between the top block and the fork, using the old spring, showed a distance of 1/4". I then looked up the suspension spring assembly in the Holovar 400 Day Clock Repair Guide, which shows full scale diagrams. It matches what I measure from the old broken spring. The bottom block is, of course broken off, and I can't measure it's original distance but using the Repair Guide I was able to determind the distrance between the top block and bottom block to be 4-19/32".
With the pendulum removed, I was able to remove the suspension spring guard and remove the remnants of the old spring, by loosening the top block retention screw. With the spring assembly removed, I was able to loosen the fork screw, removing the fork from the old spring. I removed the top block by loosening the two screws in the block. The same with the bottom block.
Now, I was ready to make a new suspension spring assembly. I first installed the new .0032" HOLOVAR spring into the top block, leaving the spring at full lenght. Then measuring off 1/4" I installed the fork. At this point I needed to shorten the length of the new suspension spring, and using the Repair Guide illustration, over which I layed my partial assembly I was able to determine the proper length and marked it by pressing the edge of my screwdriver on the spring as it layed over the illustration, creating a small crease in the spring. Using scissors, I trimmed the remainder portion of the spring off, and then installed the bottom block.
Performing these actions was not too difficult with proper light, eye magnification, and a set of jewelers screwdrivers. I did have to bear down on the block screws to get them started when first loosening them. And the slots were easily damaged. I marked one of the top b.ock screws, but it is still in good functional condition.
With the new suspension spring assembly ready, I fitted it into the clock at the top saddle, screwing the retention screw through the top block. Then I rehung the pendulum from the bottom block, using the newly narrowed securing pin, which slid smoothly into place.
Now, ready for regulation.
Adjustments
The following tests were performed in the loft room with daily temperature variations from 62 to 74 degrees F.
I fully wound the mainspring and set the clock in operation:
2013-11-28 18:04 (started) -- losing appx. 5 minutes per hour.
This is probably due to the fact that I fiddled with the pendulum regulating screw, and no doubt turned it many times away from the correct position. I should have simply left it alone.
So, using the slight discoloration on the screw shaft, I returned the pendulum regulation slide as close to the old position as I could make out.
2013-11-28 22:20 (started) -- still slow, loosing appx. 2 minutes per hour.
I further adjusted the regulation screw.
2013-11-28 23:08 (started) --still slow, time for radical measures! :)
I began to time the swing of the pendulum. I should see exactly 8 beats or swings (counting each clockwise and counter-clockwise swing as one beat). I timed the adjustment for five minutes total with a stopwatch app on my smartphone, using the lap feature to record the time for each minute's set of eight beats. Using this method, in about 25 minutes I was able to regulate the clock quite well.
It appears that 1 full rotation of the regulation nut will speed or slow the clock by 1 second per minute.
With the regulation dialed in pretty well, using these 5 minute interval checks, I'll now leave the clock for at least 12 hours, before checking it's timekeeping.
2013-11-29 01:25 (started) -- 2013-11-29 12:45 -- shows correct time!
2014-01-07 23:36 -- running a little fast, approximately 1 minute per week, currently reading 23:42.
2014-01-19 21:16 -- still a little fast, current time is 21:24. Doing some calculations shows the clock running 1.082 minutes fast per week.